16 liter COMPACT or 24 liter FLOORSTANDER
Copyright 2010 Troels Gravesen

Open kit, not supported by Jantzen Audio.
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Left: Drivers. Download specs:
CA18RLY - 22TAF/G. Right: finished 16 liter cabinets.

The CA18RLY driver is a descendent of classic drivers like the Vifa C17WH and SEAS CA17RCY drivers. A light-weight paper cone and 25 mm voice coil makes an extended range driver with relatively high sensitivity. This time we get a thoroughly vented chassis and rubber surround and as previously a smooth extended frequency response up to 6 kHz , making crossover work easy.

The 22TAF/G tweeter is totally new. A 20 mm alu dome with a wide fabric suspension combines some of the qualities of small and large domes and provides an extended response down to 1.5 kHz. An easy driver too when it comes to crossovers.

System sensitivity is 86-87 dB/2.8 volts and being an easy load this speaker can be driven from almost anything. Despite modest size it will throw a significant soundstage and should you decide on a 24 liter cabinet, an extended bass response too. Do not expect earth-quake scenarios from 135 square centimeter membrane area. Simple physics apply to this construction too.


The cabinet

Cabinet dimensions:

16 liter: 210 (W) x 360 (H) x 330 (D) from 19 mm MDF makes 16 liter.
Port = 50 (ID) x 140 mm for port tuning ~40 Hz.

24 liter: 210 (W) x 1000 (H) x 280 (D) mm. Internal height = 600 mm.
Used lower part of cabinet for sand filling and crossover. Port = 50 (ID) x 80 mm. Port tuning = 40 Hz.
Maintain driver placement with regard to upper edge of cabinet to make the crossover perform properly.

Several options are available for the CA18RLY driver. Should you want a compact monitor, 16 liter will provide decent bass to around 60 Hz with +1 dB in the lower region, where a 24 liter floorstander makes F3 = 50 Hz (port = 50 (ID) x 80 mm. To get the drivers into reasonable listening height, a 1 meter cabinet is recommended and surplus volume at bottom of cabinet can be used for sand filling and crossover.

Suggested 24 liter cabinet. Use bracing as seen in
TJL2W cabinet.


Crossover schematics.

Crossover layout.

Finished crossover hard-wired on a slant of 12 mm Baltic birch.

The Kit


Left: Frequency response from drivers mounted in 16 L cabinet without crossover attached. Right: Impedance of drivers mounted in cabinet.

Left: Final SPL @ 1 meter, 2.8 volt input.
Right: Frequency response from individual drivers driven from crossover, blue and green.
Red = summed response. Yellow = response from inverting tweeter polarity.

Impedance of final system. Overall an easy load on the amplifier.